Table III.

Incorporation of ¹⁸O into ABA in water-stressed shoot tips of Cuscuta

In two experiments, Cuscuta stem tips (25 and 20, respectively) were incubated in an atmosphere containing 20% ¹⁸O₂ in the presence of Drierite for 24 h. The tips lost 30% of their FW during the 24-h incubation period. The m/z values 278 to 284 represent the relative abundances of the molecular ion cluster with zero, one, two, and three ¹⁸O atoms incorporated, respectively.

Experiment	ABA Content	Relative Abundance				Labeled
	μg	m/z				%
		278	280	282	284
1	5.3	48	100	61	16	79
2	4.0	21	100	87	39	91